Sanitary drain system, method, and fittings therefor



Get. 17, 1967 SOMMER 3,346,887

SANITARY DRAIN SYSTEM, METHOD, AND FITTINGS THEREFOR Filed Feb, 11, 1965 6 Sheets-Sheet 1 INVENTOR FriTz Sommer BY M M M MX AW ATTORNEYS Oct. 17, 1967 SANITARY DRAIN SYSTEM, METHOD, AND FITTINGS THEREFOR Filed Feb. 11, 1965 6 Sheets-Sheet 2 INVENTOR Frifz Sommer v ATTORNEYS F. SOMMER 3,346,887 I SANITARY DRAIN SYSTEM, METHOD, AND FITTINGS THEREFOR Filed Feb. 11, 1965 6 Sheets-Sheet Ii \h: uinl .ii1

1 80 M N s'7l FIG. 13

INVENTOR Fritz Sommer ATTORNEYS Oct. 17, 1967 F. SOMMER 3,346,887

SANITARY DRAIN SYSTEM, METHOD, AND FITTINGS THEREFOR Filed Feb. ll, 1965 6 Sheets-Sheet 4 INVENTOR Fritz Sommer ATTORNEYS Oct. 17, 1967 F. SOMMER 3,346,887

SANITARY DRAIN SYSTEM, METHOD, AND FITTINGS THEREFOR Filed Feb. 11, 1965 6 SheetsSheet 5 INVENTOR 5 Friiz Sommer ATTORNEYS Oct. 17, 1967 F. SOMMER 3,346,887

SANITARY DRAIN SYSTEM, METHOD, AND FITTINGS THEREFOR Filed Feb. 11, 1965 6 Sheets-Sheet 6 INVENTOR F rirz Sommer M, w lkyfla ATTORNEYS United States Patent Ofiice 3,345,887 Patented Oct. 17, 1967 3,346,887 SANITARY DRAIN SYSTEM, METHOD, AND FITTINGS THEREFOR Fritz Somrner, Bern, Switzerland, assignor, by mesne assignments, of to each: Anaconda American Brass Company, a corporation of Connecticut; Bridgeport Brass Company, division of National Distillers and Chemical Corporation, a corporation of Virginia; Calumet & Hecla, End, a corporation of Michigan; Cerro Copper 8: Brass Company, division of Cerro Corporation, a corporation of New York; Chase Brass & Copper Co. Incorporated, a corporation of Connecticut; Mueller Brass (10., a corporation of Michigan; Phelps Dodge Copper Products Corporation, a corporation of Delaware; Reading Tube Corporation, a corporation of Delaware; Revere Copper and Brass Incorporated, a corporation of Maryland; Scovill Manufacturing Company, a corporation of Connecticut; and Triangle Couduit and Cable Co., Inc, a corporation of Delaware Filed Feb. 11, 1965, Ser. No. 431,823 14 Claims. (Cl. 4-211) ABSTRACT OF THE DISCLOSURE A sanitary drain system, especially suited for tall buildings, which does not require a separate vent stack, is based on a special aerator branch fitting by which lateral drains are connected to the stack. The special fitting provides a mixing chamber with an outlet into the drain stack at its lower end. A lateral drain connection opens into the upper end of the mixing chamber directly above the outlet, and liquid entering through the lateral connection is directed vertically downwardly through the mixing chamber to the outlet. A stack inlet connection to the drain stack above opens into the mixing chamber alongside the lateral drain connection. Liquid flowing into the fitting through the lateral drain connection is highly aerated in the mixing chamber so as not to block the outlet connection to the flow of air down the stack. The complete drain system includes a deaerator fitting at the base of the stack, where air is disengaged from liquid at the point where it is delivered into a lateral sewer.

This invention relates to sanitary drainage, especially for tall buildings, and has for its principal object preventing the development of excessive negative (or positive) pressures in drain systems. The invention provides an improved method for achieving such object; and it further provides an improved sanitary system utilizing the method of the invention and an improved aerating connector fitting for use in such system. This application is a continuation-in-part of my copending applications Ser. No. 120,318, filed June 28, 1961, since abandoned, and Ser. No. 389,817, filed Aug. 5, 1964 and since matured into Patent No. 3,287,885, dated Nov. 29, 1966, the latter being a continuation of my application Ser. No. 116,712, filed June 13, 1961, now abandoned.

Sanitary drainage systems for all buildings comprise essentially a vertical drain stack of pipes through which liquid sanitary wastes (often admixed with solids) falls substantially vertically to a sewer pipe which runs laterally with only a gentle slope to enable the liquid to flow through it to the public sanitary sewer. The drain stack includes fittings at each floor by which lateral drain pipes for the fioor are connected to the stack. Generally these fittings are simple Ts. Sanitary appliances such as toilets, wash basins, sinks and baths are connected through traps to the lateral drain pipes, which, like the sewer pipe, are gently inclined from the appliance downwardly to the stack fitting. The trap associated with each fitting is simply a U-tube which is intended to be kept filled with water to prevent obnoxious sewer gases from escaping through the appliance drain into the surrounding atmosphere.

Simple as these systems are, in operation they present a problem which is neither simple to understand, nor easy or inexpensive to solve. The problem is that when a large volume of water is discharged in a short period of time into the system, such as by flushing a toilet, such discharge will create negative (below atmospheric) pressures within the system, both at the floor when the discharge occurs and at lower floors, which often reach magnitudes great enough to suck the water out of the traps of all the appliances on the atfected floors. Such an occurrence is highly objectionable for it may result in the escape of objectionable and even hazardous amounts of sewer gas into the aifected area. A concomitant effect is the creation of excessive positive (above atmospheric) pressures at floors near the base of the stack.

Conditions which cause excessive negative pressure to develop are generally well understood. The condition chiefly responsible is the blocking of the drain stack by the waste discharge when it flows from the lateral floor drain pipe into the stack, and the entrapment of air by falling water below this point of blockage. The blocking occurs because the momentum of the liquid waste flowing through the lateral drain pipe carries it across the diameter of the vertical drain stack, at the point of connection of the lateral drain pipe to the stack, before the force of gravity can change its course to a vertical fall. Thus at this point the drain stack remains blocked for so long as the discharge flows. Meanwhile the liquid that has entered the stack falls with the acceleration of gravity, and in doing so entraps air in the stack and carries it downwardly. Air cannot flow down the stack through the point of blockage as rapidly as air entrapped by the falling liquid is carried down below that point, with the result that substantial negative pressures are developed for several floors below the point of blockage. correspondingly high positive pressures also customarily form at still lower floors. The negative pressures can easily obtain a magnitude of two to twelve inches of water, more than ample to empty all the traps on the floor of the discharge and on several floors below.

Two solutions to the above problem have been commonly used heretofore. One is to make the drain stack of substantially larger size than is necessary to carry the expected flow rates of discharged Waste, and thereby reduce the blocking effect of the flowing water when it enters the drain stack. The other is to parallel the drain stack with a separate vent stack to which is connected the trap of each appliance, or the lateral drain pipe itself near the trap. The latter solution is particuluarly effective and is in fact required by many building codes. But both solutions are costly both in terms of the excess weight of piping required and in terms of the amount of plumbing labor required.

The present invention makes available a sanitary drain method and system that provides a new solution to the foregoing problem requiring no enlargement of the drain stack piping beyond what has been employed heretofore in vented systems, and requiring no separate vent stack or system. Thus the invention enables installing sanitary drain systems in tall buildings at substantially reduced costs in comparison with the system generally employed heretofore.

The method of this invention provides for preventing development of excessive negative (and positive) pressures in a tall sanitary drain stack into which liquid waste is discharged through lateral drain pipes, by directing such liquid waste vertically downwardly in a straight line path as it enters the drain stack, and strongly aerating such waste directly upon its entry into the drain stack by bringing only the lateral boundary of the vertically directed stream into contact with air entering through the drain stack. Since only the lateral bounds of the downwardly directed stream of water comes in contact with air from the upper portions of the stack, there is substantially no blocking of the stack. The new method further contemplates separating air from the aerated liquid waste when it has fallen to the base of the drain stack, and flowing the deaerated liquid waste substantially laterally away from the base of the drain stack while separately withdrawing the separated air.

Preferably the free fall of all portions of the aerated waste is broken in its descent through the drain stack by causing it to impinge on offset portions thereof at least once each story.

A sanitary drain system according to the invention which utilizes the foregoing method comprises a vertical drain stack made up of aerating connector fittings located one at each floor connected in series by substantially vertical drain pipes. A lateral sanitary sewer pipe is located at the base of the stack, and a deaerating fitting connects the base of the stack to such sewer. One or more sanitary appliances (toilets, sinks, tubs, basins, etc.) located on each floor are connected by a lateral drain pipe to the aerating connector fitting on such floor. Each aerating fitting comprises means for strongly aerating liquid waste entering the fitting through the lateral drain pipe, as such waste falls through the fitting, substantially without blocking access of the drain stack below to access of air through the drain stack above, by directing the stream of liquid waste vertically downwardly in the fitting and exposing only the lateral boundary of the downwardly directed stream to air from the drain stack above. The deaerating fitting comprises means for arresting the fall of the aerated waste prior to its entry into the lateral sewer pipe, an further comprises means for the withdrawal or escape of air disengaged from said waste separately from the flow of the deaerated liquid waste into the entry to the sewer pipe.

A preferred aerating fitting according to the invention for connecting the lateral sanitary drain pipe to the vertical drain pipe stack comprises a body portion having side walls defining a mixing chamber, the upper portion of which has a width at least twice as great as the lower portion thereof. The body portion has a drain stack inlet connection at its upper end, a drain stack outlet connection at its lower end, and a lateral drain inlet connection.

The stack inlet connection and the lateral drain inlet o nection communicate side by side with theupper portion of the mixing chamber, and the stack outlet connection communicates with the lower portion of the mixing chamher. The side wall of the mixing chamber between the lateral drain inlet connection and the stack outlet connection is vertical and parallel to the axis of the. outlet connection, whereas the opposite side wall is divergent upwardly and away from said axis. A guide plate within the fitting above the mixing chamber is positioned to direct substantially the entire volume of liquid flowing into the fitting through the lateral inlet connection in a straight line vertical path downwardly through the mixing chamber to the stack outlet connection. The stack inlet connection communicates with the upper portion of the mixing chamber on the side of the guide plate opposite the lateral drain inlet connection, and isdisplaced laterally from the stack outlet connection by at least the diameter of said outlet, so that there is no straight line path for the flow of fluid through the mixing chamber from the stack inlet to the stack outlet.

Preferably the guide plate is spaced from one or more walls of the fitting, or is otherwise arranged or formed, to provide openings through which air may be aspirated from the stack inlet connection into liquid entering the fitting through the lateral drain connection as the liquid is directed downwardly.

The vertical height of the mixing chamber, and the mixing area it provides, must be adequate and substantial. The vertical height of such chamber, from the bottom of the guide plate to the region of minimum cross section adjacent the stack outlet connection, is at least twice the diameter of the stack outlet connection, and is advantageously at least about three times such diameter. The mixing area provided by the mixing chamber interiorly of the fitting, measured on the surface defined by a plane which is parallel to the axis of the stack outlet connection and which bisects and is normal to the major axis of the mixing chamber at its upper end, exceeds at least twice the cross sectional area of the stack outlet connection.

The stack inlet connection of thefitting is preferably disposed above the lateral inlet connection and is centered substantially about the same vertical axis as the stack outlet connection. The stack inlet connection then advantageously forms a part of an offset conduit connected to the upper portion of the mixing chamber on the opposite side of the guide plate from the lateral inlet con nection; and the axis of the connection of such offset conduit to the mixing chamber is displaced laterally from the axis of the stack inlet and outlet connections by at least the diameter of said connections. Such an offset conduit will assure interrupting the free fall of all parts of t e stream of aerated waste coming from the drain stack above the fitting. Preferably the axis of the offset conduit should at all points form an angle not greater than 45, and preferably not greater than 30, to the vertical axis of the stack inlet and outlet connections, to prevent accumulation on the walls of the offset conduit of any solid constituents of the waste.

Advantageous and presently preferred embodiments of the invention are described below in connection with the accompanying drawings, in which FIG. 1 is a view of a drain pipe system according to the present invention;

FIG. 2 is a diagram illustrating typical pressure variations that develop in the system of FIG. 1, corresponding portion of FIGS. 1 and 2 being shown at the same horizontal level;

FIG. 3 is a vertical sectional view of an aerating connector fitting according to the invention;

FIG. 4 is an elevation of the fitting of FIG. 3, viewed from the left;

FIG. 5 is a top view of the fitting of FIG. 3, partly in section taken along the line 5-5;

FIG. 6 is an elevation, partly in section, and FIG. 7 is a top view of a form of fitting according to the invention which can readily be fabricated from sheet metal;

FIG. 8 is a vertical sectional view of a modified type of aerating fitting according to the invention, and FIGS. 9, 10, and 11 are cross sectional views of the fitting of FIG. 8 taken respectively on the lines 99, 1010, and 11-11;

FIG. 12 is an elevation and FIG. 13 is a top view of another modification of the aerating fitting of the invention;

FIG. 14 is a vertical sectional View, FIG. 15 is a top view, and FIG. 16 is a cross section taken on the line 16-16 of FIG. 14, of yet another modification of the aerating fitting of the invention;

FIG. 17 is a vertical sectional view of a further modification of an aerating fitting according to the invention;

FIG. 18 is an elevation partly in section, FIG. 19 is an end elevation, and FIG. 20 is a top view of a one more aerating fitting according to the invention;

FIG. 21 is a vertical sectional view of a deaerating fitting suitable for use in drain systems according to the invention; and

FIG. 22 is a top view and FIG. 23 is a section taken along the line 2323 of the deaerating fitting of FIG. 21.

The drain system of FIG. 1 comprises a vertical drain.

stack 25 for collecting the waste discharged from sanitary appliances, such as toilets 26 and basins 27 on various floors of a multi-story building, and delivering such waste to a sewer pipe 28. The drain stack is made up of aerating fittings 29 located one at the level of each floor and lengths of drain pipe 30 connecting the fittings in series. At the base of the stack is a deaerating fitting 31 through which the lowermost length of stack drain pipe 30 is connected to the sewer pipe 28. The sanitary appliances on each floor are connected by a lateral drain pipe 32 to the aerating fitting located at that floor level.

Each aerating fitting 29 provides for strongly, aerating the waste delivered to it from the sanitary appliances on its floor level. An important feature of each fitting 29 for accomplishing this purpose is the provision within each of a guide plate 33 by which liquid waste flowing into the fitting from the lateral drain pipe is directed vertically downwardly into the drain pipe next below. Within each fitting below the guide plate is a mixing chamber wherein only the lateral bounds of the incoming downwardly directed stream of waste are in contact with air entering through the drain pipe next above. Such air enters the mixing chamber only through a conduit or passage connected to it on the opposite side of the guide plate from the connection to the lateral drain pipe 32.

The connections of the stack drain pipes to the top and bottom of each fitting are on a substantially common vertical axis. However, the conduit or passage within each fitting through which communication is provided between the mixing chamber and the stack drain pipe above is offset laterally by at least the diameter of such pipe, since the guide plate 33 is spaced from the wall of the fitting through which the lateral drain pipe 32 connects by at least the diameter of the stack drain pipe. Hence the free fall of all portions of waste descending through the stack 25 is interrupted at least once every second floor.

The deaerating fitting 31 includes an internal projection 35 by which the fall of aerated waste is arrested somewhat prior to its entry into the sewer pipe. It further includes an air vent conduit 36 by which air disengaged from the waste in the deaerator is withdrawn separately from the deaerated liquid waste which discharges into the sewer pipe 28. The conduit 36 is shown in FIG. 1 as being connected to the upper surface of the sewer pipe 28 at a point beyond the deaerating fitting, so that the disengaged air can be vented through the sewer system above the flowing surface of the liquid sewage (which does not completely fill the pipe 28). In many cases, however, it is preferable and simpler to vent the conduit 36 to the outdoor atmosphere. It is always possible to lead this conduit to a location where such venting is unobjectionable, as is done in conventional vented drain systems.

In operation of the system described above, the method of the invention is carried out as follows: When one or more of the toilets 26 is flushed, a substantial flow of water and waste is delivered in a short period of time into the lateral drain pipe 32. For example, a typical low pressure toilet tank contains three gallons of water and will empty in six seconds. Thus for this period of time a flow at the rate of thirty gallons per minute is discharged into the fitting 29; and if two or three toilets are flushed approximately at the same time, the rate of waste water fiow is doubled or tripled.

As the waste water enters the fitting 29, the configuration of its connection to the lateral drain pipe, and more particularly the guide plate 33, direct the stream vertically downwardly in a straight line path to the stack drain pipe below. The wall of the fitting has no slope or projection by which any part of the incoming stream can be deflected across the passage communicating with the drain stack above. Only lateral bounds of the stream are brought in contact with air from the upper portion of the drain stack. The falling stream of water rapidly breaks up and air readily penetrates the lateral boundary of the vertically directed stream. Thus there is substantially no blocking of the flow of air through the fitting as the waste water discharges into and through it. Instead, the waste is strongly aerated and falls from the fitting as an aerated mass through which air flow proceeds easily, and no opportunity is presented for the development in the drain stack of excessive pressures, either negative or positive.

The falling mass of aerated waste discharged from one fitting 29 has its free fall interrupted as soon as it reaches the fitting at the floor next below. Here the offset passage through which the falling mass must enter the mixing chamber of such next lower fitting is impinged by such mass, slowing its rate of fall markedly. Such interruption in the fall of the Waste occurs at least once every second floor as it passes through the aerator fitting. Consequently the aerated mass of waste has no opportunity to accelerate to a very high velocity, and as a result its tendency to create a downward flow of air through the drain stack is markedly reduced. The open aerated character of the falling mass which permits ready flow of air through it to equalize pressure differentials, and its relatively slow interrupted fall and consequently reduced tendency to force a downward flow of air in the stack, cooperate to prevent development of excessive negative (or positive) pressures anywhere in the drain stack system.

At the bottom of the drain stack the falling aerated mass of liquid waste enters the deaerating fitting 31. Here its fall is arrested by the projection 35. In the relatively large interior volume of the deaerator, the air in the mass is easily disengaged from the liquid. The d'eaerated liquid flows out the bottom of the deaerator into the sewer pipe 28, and the disengaged air is free to be withdrawn separately through the air vent conduit 36 (which, as stated above, may be open to the atmosphere instead of being connected to the sewer).

FIG. 2 graphically illustrates the notable reduction in negative pressure within a drain stack system according to the invention, as described above, in comparison With a similar unvented system of conventional construction using simple 87 Ts at each floor level to connect the lateral drain pipes to the vertical drain stack. Curve I shows the negative pressures developed at various floors when a flow of 400 liters per minute (above gallons per minute, corresponding to the discharge from three toilets flushed simultaneously) was delivered into the drain stack at the top floor. The maximum negative pressure was less than 3 mm., far less than would suflice to suck out a trap. Curve II shows the negative pressure developed under similar flow conditions in a similar conventional system with 87 T connections instead of aerating fittings. Here the negative pressure on all four floors next below exceeded 100 mm. (approximately 4 inches) and sufiiced to empty all traps connected to the system on all these floors. (The curves are not plotted to the same horizontal scale --the horizontal scale of curve I is much greater than that of curve II.)

Curve III shows the pressure conditions developed in the system of the invention when four toilets are flushed simultaneously on the top floor. Even under these conditions the negative pressure developed does not exceed 4 mm. at any floor level.

Various specific designs of aerating fitting 29 are shown in FIGS. 3 to 20. The fitting of FIGS. 3 to 5 comprises a body member generally indicated at 40, the side Walls of which enclose a mixing chamber 41. A stack inlet connection 42 at the upper end of the fitting provides for connection to the upper section of the drain stack. A stack outlet connection 43 at the bottom of the fitting provides for connection to the lower section of the drain stack. The stack inlet and stack outlet connections are centered about a common vertical axis 44. A lateral drain inlet connection 45 extends laterally from one side of the fitting and provides for connection to the lateral drain pipe through which waste flows to the vertical drain stack.

One side wall 46 of the fitting body extends straight and vertical, parallel to the axis of the stack outlet connection, from the outlet connection to the top of the mixing chamber, and then curves outwardly at 47 to form part of a tubular passage 48 leading from the lateral'drain inlet connection to the mixing chamber. The opposite side wall 50 of the fitting body diverges outwardly and upwardly from the stack outlet connection 43 to the top of the mixing chamber 41, making the width of that chamber at its top, along its major axis 51, a little over twice as great as its width at the bottom where it joins the stack outlet connection, the latter width corresponding substantially to the diameter 52 of the stack outlet connection. The fitting wall 50 thence curves inwardly and upwardly to the stack inlet connection 42, forming part of an offset conduit or passage 53 providing communication between the stack inlet connection and the mixing chamber.

Within the fitting is a guide plate or surface 54, located above the mixing chamber and disposed between the conduits 48 and 53. Indeed, in the form of fitting shown in FIG. 3, the guide plate serves also to define a common wall of these two conduits, which open side by side into the top of the mixing chamber.

The guide plate 54 serves to direct waste entering the fitting through the lateral drain connection vertically downwardly through the mixing chamber in a straight line path indicated by the arrows to the stack outlet connection. No offset surfaces or projections allow for any of this waste, even under conditions ofhigh rate of flow, to1be deflected with a horizontal component to the opposite side wall 50 and thus partially block the fiow of air from the stack inlet connection. A slight in-turned projection 55 may even be formed at the base of the guide plate 54 to deflect the waste away from across the mixing chamber, but such a provision is not essential.

It will be noted that the conduit 53 communicates with the upper portion of the mixing chamber on an axis 56 which is displaced laterally from the common axis 44 of the stack inlet and outlet by at least the diameter of the stack outlet. Thus there is no straight line path through the mixing chamber for the flow of fluid from the stack inlet connection. All portions of waste liquid dropping through the stack inlet connection must impinge on, or be deflected by, the otfset wall of the conduit 53, thus interrupting such free fall and preventing undue acceleration of waste dropping downthe stack. To prevent adherence and collection of solid constituents of the waste on the wall of the offset conduit, its axis 56 should at no point lie at an angle A less than 45 with the axis 44 of the stack inlet, and preferably such angle should be no greater than Similarly, the sloping wall 50 of the fitting should not at any point make an angle B greater than and preferably not greater than 30, with the axis 44 of the stack inlet connection.

For adequate aeration of the waste liquid entering the fitting through the lateral drain connection 45,and to assure against any substantial blocking by waste inflow of the flow of air down through the fitting from the stack above, the dimensions of the mixing chamber must be substantial. Especially, its height and mixing area must be sufiicient. Its vertical height, measured from the bottom of the guide plate 54 along the line 57, should be at least twice the diameter of the stack outlet connection, and preferably three times such diameter. The mixing area, taken on a plane on line 57 normal to the elevation of FIG. 3, which is parallel to the stack outlet axis 44 and which bisects and is normal to the major axis 51 of the upper portion of the mixing chamber, should be upwards of twice, and preferably more than three times, the cross sectional area of the stack outlet connection.

When waste liquid is being discharged through the fitting, it is channeled in a straight line vertical path downwardly through the mixing chamber and only its lateral boundary comes in contact with air and aerated waste from the stack above. Along this boundary it easily breaks up into droplets intermixed with air, so that it is strongly aerated by the time it leaves the fitting. There is no blockage along this boundary to the substantially free flow of air from the stack above to thestack below, so that air pressure in the stack below the fitting is readily equalized with the pressure above (ultimately with atrnos pheric pressure for the stack is open at the top to the atmosphere). This use of the fitting in a drain system as described above contributes importantly to preventing development of excessive negative pressures in the stack at and below the point of discharge into the stack of large volumes of waste water.

The aerating fitting shown in FIGS. 6 and 7 is basically the same as that shown in FIGS. 3 to 5, except that it is designedprimarily for fabrication from sheet metal. Its body member 60 is bent and seamed from a single sheet, and is closed at the top by a coverv member 61. At the bottom it is joined to a tubular stack outlet connection 62 for attachment to a stack drain pipe. The cover 61 is provided with cylindrical connection members 63 and 64. One such member 63 is the lateral drain inlet connection and directly overlies the stack outlet connection 62. It receives an elbow 65 or like fitting which serves to conduct waste liquid into the fitting. The other member 64 Y is the stack inlet connection and receives an offset conduit 66 or other means for connecting the fitting to the upper section of the drain stack. A sheet metal guide plate 67, which may be curved correspondingly with the connection member 63, depends into the fitting from such member or from the fitting cover 61.

The fitting of FIGS. 8 to 11 also is in most respects of the same design as that of FIGS. 3 to 5, but is designed to be assembled by welding from separately cast parts (or from parts formed from tubing) rather than to be cast in one piece. The body member 70 is welded to a cylindrical stack outlet connection 71 and to a cover plate 72. The cover plate is apertured to receive an elbow 73 which forms the lateral waste drain connection, and to receive an offset conduit 74 the upper portion 75 of which forms the stack inlet connection. The geometrical arrangement and proportions of the stack inlet and outlet connections, the lateral drain inlet connection, and the mixing chamber enclosed by the body member are all substantially as described in connection with FIGS. 3 to 5.

Within the body member 70, but not attachedto it, is a guide plate 76. This guide plate may be welded or otherwise attached to the elbow 73 or to the cover plate 72, but as best shown in FIG. 10 it is spaced from the walls of the body member to provide apertures 77 above the mixing chamber (which lies below the guide plate 76) through which air may be aspirated from the inlet stack connection into the liquid waste as it is deflected vertically downwardly into the mixing chamber by the guide plate. The provision of such apertures assists in some cases in aerating the incoming liquid waste.

The fitting of FIGS. 12 and 13 is generally the same as that of FIGS. 8 to 11, except that it has a lateral drain inlet connection provided by an elbow 80 which is mounted on the body member 81 so as to face at to the direction of the corresponding elbow 73 of FIG. 8. The offset stack inlet conduit 82 and the stack outlet connection 83 are of the same design and arrangement as the corresponding parts in FIG. 8.-The guide plate 84 may be spaced from the walls of the fitting as shown in FIG. 10, or may be in contact with such walls, as desired.

The fitting of FIGS. 14 to 16 comprises a body member 90 formed with a stack outlet connection 91 at its base, a lateral drain inlet connection 92 to receive liquid waste discharges, and a stack inlet connection 93. A guide plate 94 within the body member serves to direct incoming liquid waste entering through the lateral drain connection vertically downwardly in a straight line path to the stack outlet. The general proportion and arrangements of these.

parts are generally the same as described in connection with FIGS. 3 to 5, except in two respects. First, the fitting is simplified and shortened by omitting the offset conduit between the stack inlet connection and the upper part of the mixing chamber (without, however, allowing any straight line path for the flow of fluid from the stack inlet connection through the mixing chamber to the stack outlet connection). In order to install this fitting in a vertical drain stack, therefore, it is necessary either to do so through an offset conduit connected either to the stack inlet or stack outlet connection, or to install the drain pipes that joins fittings on diflerent floors at an angle to the vertical. Either arrangement can be employed successfully. It is also possible to install the lengths of stack drain pipe vertically without using any offset conduits, but then each successive length of pipe will have to be displaced laterally from the preceding length, giving an overall slope to the stack which in most installations is undesirable.

The second major departure in the design of the fitting of FIG. 14 from that of FIG. 3 is that the guide plate 94 is spaced from the fitting body wall at the top to provide an aperture 95 above the point at which liquid waste entering through the lateral drain connection 92 will impinge on the guide plate. This aperture, like the apertures 77 in FIG. 10, provides for aspirating air into the incoming liquid waste from the stack inlet connection 93. The high location of the aperture 95 minimizes the chance for any part of the liquid waste to avoid the vertical downward guidance provided by the guide plate.

The fitting of FIGS. 14 to 16 also is provided with bosses 96 by which small lateral drain pipes may be tapped into the fitting. These bosses are intended to take only small lateral drains which cannot deliver a sufiicient volume of liquid into the fitting to block the free flow of air through it or the stack, and which is too small also to divert a major inflow of liquid waste entering simultaneously through the lateral drain connection from the vertical straight line path downwardly through the mixing chamber which such major inflow is caused to take by the guide plate.

The fitting of FIG. 17 is generally the same as that of FIGS. 14 to 16, except that the body member 100 is formed with an integral oifset conduit 101 connecting the upper portion of the mixing chamber 102 with the stack inlet connection 103. The arrangement of the lateral drain inlet connection 104, guide plate 105, and stack outlet connection 106, are all substantially as described in connection with FIG. 14.

The fitting of FIGS. 18 to is much like that of FIG. 17. Here, however, the body member 110 is integral with a conduit portion 111 which faces upwardly at an angle of about to the vertical. This conduit portion is joined to a standard 30 elbow 112 to provide the stack inlet connection 113. The stack outlet connection 114 is similar to that shown in FIG, 3. Instead of only one lateral drain inlet, three such inlets 115 facing 90 apart are provided. The guide plate 116 is spaced from the top of the fitting to provide an aperture 117 for aspirating air into liquid waste as it discharges into the fitting through the lateral drain connection. Bosses 118 are provided on the fitting body member for tapping in small drain pipes, as in the fitting of FIGS. 14 to 16. Any such small drains must of course be incapable of delivering a volume of liquid waste large enough substantially to impede flow of air through the fitting, or large enough to divert the major flow of incoming waste from its vertical straight line path down through the mixing chamber.

FIGS. 21 to 23 show an advantageous form of deaerating fitting such as may be used for the fitting 31 in the system of FIG. 1. This fitting comprises a body member 120 which encloses an air separation chamber 121 tapering from small cross sectional area at the bottom to large cross section area at the top. At the bottom of the chamber the fitting is provided with a sewer outlet connection 122, and at the top it is provided with a stack inlet connection 123 and with an air vent connection 124. Both these connections open through the top of the body member into the 1% air separation chamber to minimize the height of the fitting and the space it requires. Advantageously, the sewer connection 122 and the stack inlet connection 123 are centered about a common vertical axis 125.

In position to intercept and arrest the fall of aerated waste entering the fitting through the stack inlet connection is a projection 126 extending into the air separation chamber 121. This projection extends inwardly for a distance less than the diameter of the stack inlet connection, however. The upper surface 127 of this projection, which receives the impact of the falling waste, slopes downwardly and inwardly from a side wall of the fitting at an angle C to the vertical which is not greater than 45 and preferably is not substantially greater than 30, so that solid constituents of the falling waste do not tend to collect or build up a deposit on the projection.

Falling waste which enters the fitting impinges on the sloping surface 127 of the fitting and is deflected thereby laterally toward the opposite wall of the air separation ch amber. Although a straight line path exists for some portion of the falling waste from the stack inlet connection to and through the sewer outlet connection, substantially all waste falling along this path is intercepted and deflected laterally by the waste that impinges on and is deflected by the projection 126.

The effect of the interception and deflection of the falling waste is to arrest its fall and promote a swirling motion of the aerated mass in the air separation chamber. This separation is promoted by the arrangement of the sewer outlet directly below the stack inlet connection, for it requires the deflected liquid waste to return again to the side of the separation chamber where it entered, and thus causes its retention in the chamber a trifle longer than would otherwise be the case and increases the swirling motion. Swirling also is promoted by the arrangement of the propection 126 so as to directly intercept only part of the incoming stream and to cause the deflected portion of the stream to impinge on the undeflected portion. As a result of the arrest of its fall and its swirling motion, the heavy liquid and solid constituents of the waste are given a chance to separate from the air. These heavy constituents settle quickly and drop through the sewer outlet connection. The disengaged air, to the extent it may be under a slight positive pressure, is free to pass out through the air vent connection 124. As indicated in FIG. 1, this air vent connection may be joined by a conduit to the air space above the waste in the sewer line, but generally it is more satisfactory to leave it open to the atmosphere, or to connect it to a short vent leading to the outdoor atmosphere through a building wall.

While the form of deaerating fitting shown in FIGS. 21 to 23 is particularly advantageous, many other shapes and designs of deaerators may be used successfully in the drain system and in carrying out the method of the in vention. In the absence of any such fitting, as when a simple elbow connects the drain stack to the sewer, the falling aerated mass builds up a foamy accumulation where its fall is abruptly stopped and its flow direction changed, with the result that the entrance to the sewer is partially blocked, and the opportunity for air at a slight positive pressure to escape is prevented. This leads to the development of greater positive pressures in the drain stack system than occur when a deaerating fitting is employed. Virtually any fitting or arrangement that provides for withdrawal or escape of disengaged air separately from the liquid and solid waste just before the latter enters the lateral sewer pipe will serve effectively as a deaerating fitting, and especially so if it provides also for arresting the fall of the aerated mass in a chamber of ample volume for the air to disengage from the waste just before the waste enters the sewer.

I claim:

1. An aerating fitting for connecting a lateral sanitary drain pipe to a vertical drain pipe stack comprising a body portion having side walls defining a mixing chamber, the upper portion of saidmixing chamber having a width at least twice as great as the lower portion thereof, said body portion having a drain stack inlet connection at its upper end, a drain stack outlet connection at its lower end, and a lateral drain inlet connection, said stack inlet connection and said lateral drain inlet connection communicating said by side with the upper portion of the mixing chamber and said stack outlet communicating with the lower portion of the mixing chamber, a side wall of the mixing chamber between the lateral drain inlet connection and the stack outlet connection being vertical and parallel to the axis of said outlet connection and the opposite side wall being divergent upwardly and away from said axis, a guide plate within the fitting above the mixing chamber in position to direct substantially the entire volume of liquid flowing into the fitting through the lateral inlet connection downwardly in a straight line vertical path through the mixing chamber to the stack outlet connection, the stack inlet connection communicating.

with the upper portion of themixing chamber on the side of said guide plate opposite the lateral drain inlet connection and on an axis displaced laterally from the axis of the stack outlet connection by at least the diameter of said outlet, whereby there is no straight line path for the flow of fluid through the mixing chamber from the stack inlet to the stack outlet.

2. An aerating fitting according to claim 1, in which the guide plate is provided with openings through which air may be aspirated from the stack inlet into liquid entering the fitting through the lateral drain connection as it is directed downwardly.

3. An aerating fitting according to claim 1, in which the vertical height of the mixing chamber from the bottom of the guide plate to the region of minimum cross section adjacent the stack outlet connection is at least twice the diameter of the stack outlet connection.

4. An aerating fitting according to claim 1, in which the mixing area provided in the mixing chamber on the surface defined by a plane which is parallel to the axis of the stack outlet connection and which bisects and is normal to the major axis of the mixing chamber at its upper end exceeds twice the cross sectional area of the stack outlet connection.

5. An aerating fitting for connecting a lateral sanitary drain pipe to a vertical drain pipe stack comprising a body portion having side walls defining a mixing chamber, the upper portion of the mixing chamber having a width at least twice as great as its lower portion, a lateral drain connection projecting from a side wall of said fitting above the mixing chamber, a stack outlet connection communicating with said mixing chamber at its lower end, said side wall being vertical and parallel to the axis of the stack outlet and the opposite side wall diverging upwardly from said outlet to the wide portion of the mixing chamber, a guide plate within the fitting in positionto direct substantially the entire volume of liquid entering through the lateral connection downwardly in a straight line vertical path through the mixing chamber substantially along the axis of the outlet connection to such outlet, and a stack inlet connection above the lateral inlet connection centered substantially about the same vertical axis as the stack outlet connection, said inlet connection forming the upper part of an offset conduit connected to the upper portion of the mixing chamber at the opposite side of said guide plate from the lateral inlet connection, the axis of the connection of said offset conduit to said mixing chamber being displaced laterally from the axis of the stack inlet and outlet connections by at least the diameter of said outlet, whereby there is no straight line path for the flow of fluid from the stack inlet to the stack outlet.

6. An aerating fitting according to claim 5, in which the guide plate is spaced from a wall of the fitting to form an aperture through which air may be aspirated from the inlet connection into liquid entering the fitting through the lateral drain connection as it is directed downwardly by the guide plate.

7. An aerating fitting according to claim 5, in which the vertical height of the mixing chamber below the bottom of the guide plate is atleast about three times the diameter of the stack connection.

8. An aerating fitting according to claim 5, in which the mixing area provided in the mixing chamber on the surface defined by a plane which is parallel to the axis of the stack outlet connection and which bisects and is pormal to the major axis of the mixing chamber at its upper end exceeds twice the cross sectional area of the stack outlet connection.

9. An aerating fitting according to claim 5, in which the axis of the offset conduit between the stack inlet connection and the upper portion of the mixing chamber at no point forms an angle greater than 45 to the axis of the stack inlet and outlet connection.

10. The method of preventing development of excessive negative pressure in a tall sanitary drain stack into which liquid waste is discharged through lateral drain pipes, which comprises directing said liquid waste vertically downwardly in a straight line path as it enters the drain stack, strongly aerating said waste directly upon its entry into the drain stack by bringing only the lateralboundary of the vertically directed stream into contact.

with air entering through the drain stack above, separating air from the aerated mixture when it has fallen to the base of the drain stack, and flowing the deaerated liquid substantially laterally away from the base of the drain stack.

11. The method of preventing development of excessive negative pressures in a multi-story vertical drain stack into which liquid waste is discharged intermittently through lateral drain pipes, which comprises strongly aerating said waste directly upon its entry into the drain stack, breaking the fall of all portions of the aerated waste by causing it to impinge on an offset surface of the drain stack at least once every second story as it fallsthrough said stack, separating air from the aerated mixture when it has fallen to the base of the drain stack, and flowing the deaerated liquid substantially laterally away from the base of the drain stack.

12. A sanitary system for multi-floor buildings comprising a vertical drain stack made up of aerating connector fittings located one at each or every second floor connected in series by substantially vertical drain pipes,

a lateral sanitary sewer pipe at the base of said stack, a

deaerating fitting connecting said stack to said sewer pipe, a sanitary appliance on each floor connected by a lateral drain pipe to the aerating connector fitting on such floor,

each aerating fitting comprising means for strongly aerat-.

ing liquid waste entering such fitting through the lateral drain pipe as such waste falls through the fitting without substantially blocking the free flow of air through drain stack, said means serving to direct the waste vertically downwardly in the fitting and permitting exposure of only the lateral boundary of the downwardly directed stream to air from the drain stack above, and the deaerating fitting comprising means for arresting the fall of aerated waste prior to its entry into the lateral sewer pipe, and

means for the withdrawal of air disengaged from said waste separately from the flow of the deaerated liquid waste into the sewer pipe.

13. A sanitary system according to claim 12, including means for interrupting the free fall of all portions of the aerated liquid waste at least once every second story as it drops through the drain stack.

14. A sanitary system for multi-floor buildings comprisinga vertical drain stack made up of aerating connector fittings located one at each floor connected in series by substantially vertical stack drain pipes, a lateral sanitary sewer pipe at, the base of said stack, a deaerating fitting connecting said stack to said sewer pipe, and sanitary appliances on each floor connected by lateral drain pipes to the aerating connector fitting on such floor, each of said aerating connector fittings having a body portion enclosing a mixing chamber, a guide plate in said mixing chamber positioned to direct liquid waste entering said chamber through the lateral drain pipe vertically downwardly in a straight line path into the stack drain pipe next below, and a stack inlet connection to the mixing chamber joined to the stack drain pipe next above, said stack inlet connection to the mixing chamber being on the opposite side of said guide plate from which liquid waste enters through the lateral drain pipe and being on an axis ofiset laterally from the axis of the connection to the stack drain pipe next below by at least the diameter of such stack drain pipe, and said deareating fitting having a body portion enclosing an air separation chamber, a stack inlet connection adjacent to the upper end of said air separation chamber joined to the lower end of the drain stack, a sewer outlet connection adjacent the lower sanitary sewer, an air vent connection adjacent the upper end of said air separation chamber, and deflector means in said air separation chamber for arresting the fall of aerated waste entering the air separation chamber from the drain stack.

References Cited UNITED STATES PATENTS 1,186,280 6/1916 Carson 4-211XR 1,878,948 9/1932 Lulf 285-154 1,941,926 1/1934 Boosey 4-211 2,065,523 12/ 1936 Groeniger. 2,302,617 11/1942 Little 285-122 FOREIGN PATENTS 445,872 9/1912 France. 324,719 9/ 1920 Germany.

LAVERNE D. GEIGER, Primary Examiner.

end of said air separation chamber joined to the lateral 20 H. J. GROSS, Assistant Examiner. 

1. AN AERATING FITTING FOR CONNECTING A LATERAL SANITARY DRIAN PIPE TO A VERTICAL DRAIN STACK COMPRISING A BODY PORTION HAVING SIDE WALLS DEFINING A MIXING CHAMBER, THE UPPER PORTION OF SAID MIXING CHAMBER HAVING A WIDTH AT LEAST TWICE AS GREAT AS THE LOWER PORTION THEREOF, SAID BODY PORTION HAVING A DRAIN STACK INLET CONNECTION AT ITS UPPER END, A DRAIN STACK OUTLET CONNECTION AT ITS LOWER END, AND A LATERAL DRAIN INLET CONNECTIN, SAID STACK INLET CONNECTION AND SAID LATERAL DRAIN INLET CONNECTION COMMUNICATING SAID BY SIDE WITH THE UPPER PORTION OF THE MIXING CHAMBER AND SAID STACK OUTLET COMMUNICATING WITH THE LOWER PORTION OF THE MIXING CHAMBER, A SIDE WALL OF THE MIXING CHAMBER BETWEEN THE LATERAL DRAIN INLET CONNECTION AND THE STACK OUTLET CONNECTION BEING VERTICAL AND PARALLEL TO THE AXIS OF SAID OUTLET CONNECTION AND THE OPPOSITE SIDE ALL BEING DIVERGENT UPWARDLY AND AWAY FROM SAID AXIS, A GUIDE PLATE WITHIN THE FITTING ABOVE THE MIXING CHAMBER IN POSITION TO DIRECT SUBSTANTIALLY THE ENTIRE VOLUME OF LIQUID FLOWING INTO THE FITTING THROUGH THE LATERAL INLET CONNECTION DOWNWARDLY IN A STRAIGHT LINE VERTICAL PATH THROUGH THE MIXING CHAMBER TO THE STACK OUTLET CONNECTION, THE STACK INLET CONNECTION COMMUNICATING WITH THE UPPER PORTION OF THE MIXING CHAMBER ON THE SIDE OF SAID GUIDE PLATE OPPOSITE THE LATERAL DRAIN INLET CONNECTION AND ON AN AXIS DISPLACED LATERALLY FROM THE AXIS OF THE STACK OUTLET CONNECTION BY AT LEAST THE DIAMETER OF SAID OUTLET, WHEREBY THERE IS NO STRAIGHT LINE PATH FOR THE FLOW OF FLUID THROUGH THE MIXING CHAMBER FROM THE STACK INLET TO THE STACK OUTLET. 